Analysis of gaseous mixtures



March 3, 1959 w. R. EDWARDS EIT AL 2,875,849 ANALYSIS 0F GAsEbUs MIXTURES Filed oqt. 11, 1957 VENTS GSEOUS IIXTURE .y INVENTORS. WILLIAM R. EDwAR os,

DANIEL E.N|CHOLSON, GILBERT A. REI'DLAND,

gaseous mixtures.

'United Safes Para ANALYSIS F GASEOUS MIXTURS William R. Edwards, Daniel E. Nicholson, and Gilbert A.

Reidland, Harris County, Tex., assignors, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, N. J., a corporation of Delaware Application October 11, 1957, Serial No. 689,649

9 Claims. (Cl. 18S- 115) The present invention is directed to the analysis of More particularly, the invention is directed to an improved method of partition chromatography. In its more specific aspects, the invention is directed to gas-liquid partition chromatography employing a substrate.

The invention may be briefly described as a method for analyzing gaseous mixtures which comprises contact. ing a gaseous mixture in a stream of an inert gasin an elongated column packed with a-support such as diatomaceous earth, acid treated rebrick, and the like, having a mesh size in the range from about 40 to about 60 at temperatures in the range from about A'60 to about 120 F. and for a time within the range from about 5 to about 90 minutes, the support such as lrebrick or diatornaceous earth being employed with a suicient amount of benzyl cellosolve as a substrate. On contacting the gaseous mixture with the rebrick or diatomaceous earth support and substrate, the mixture is separated into` its component parts. f

The inert gas is preferably helium, but other inert gases may be employed, such as argon, nitrogen, or hydrogen.

Temperatures employed in the practice of the present invention may range from about 60 to about 120 F. with a preferred temperature range from about 75 to about 90 F.

The substrate employed in the present invention is benzyl Cellosolve, which is 2-(benzyloxy) ethanol and is employed in an amount in the range from about 20 to about 60 percent by weight of the firebrick or diatomaceous earth. The rebrick or other support containing about 40 percent by weight of benzyl cellosolve gives desirable results. While acid treated rebrick or acid treated diatomaceous earth such as Celite (which is unred diatomaceous earth) are preferred supports, other supports such as pumice, silica gel, activated carbon, and similar finely divided inert materials may be used.

The present invention may be employed to separate gaseous hydrocarbon mixtures into their component parts, separating hydrogen suliide from mixtures containing it, sulfur dioxide from mixtures thereof, carbon dioxide, and the like. Water, acetone, and C4 hydrocarbons also may be resolved in accordance with the present invention.

The gaseous mixture undergoing analysis may contact the rebrick containing the Cellosolve or be retained thereon for a time within the range from about 5 to `about 90 minutes. Exemplary of the type of compound and the retentiontime which are suitable in the practice 2,875,849 wat .3 155 ICE i 2 of the present invention will be lfound in the following table:

Compound: Retention time, minutes' All Methane 5.3' Ethane 6.1 Ethylene k6.13 Hydrogen sulfide 6.6 Sulfur dioxide 6.6 Carbon dioxide 6.7 Propane 8.1 Pr'opylene Isobutane v10.5 Neo pentane 13.0 Normal butane 13.18 lso butene 17.4 Butene-l y17.4 Butadienel,3 19.6 Trans-butene-Z 20.4 Iso' pentane 22.0 Cis-butene-2 23.7 S-methylbutene-l 26.1 Butadiene-1,2 26.3 Methyl chloride Normal pentane 28.8 Neo hexane 35.2 Pentene-l 37.8 2-methylb'utene-l 40.1 2-methylbutene-2 44.0 TransV-pentene-Z 47.9Y 2,3 dimethylbutane 48.71` Iso hexane 49.9 Cis-pentene-Z 51.8 4-methylpentene-1 60.7 3-methylpentene'1 `61L`Of Hexene-l 84.5

The present invention will be further illustrated by reference to the drawing in which the sole figure is in the form of a flow sheet of a preferred mode.

Referring now to the drawing, atank 11 containing an inert gas, such as helium, is provided which is controlled by a valve 12. A line 13 leads into a pressure regulator 14 which suitably reduces the pressure and discharges helium by way of line 15 into line 16. Admitted into line 16 is the gaseous mixture which may be a hydrocarbon mixture, by way of line 17 controlled by valve 18, the helium and gas mixture then owing by line 19 into the chromatographic column 20, which is packed with benzyl Cellosolve and rebrick as indicated by the packing 21. The packing 21 resolves the gaseous mixture` into its component parts which ow sequentially from the column 20 by way of line 22 into a thermal conductivity cell 23 which, by difference in thermal conductivity, indicates the presence 'and amounts of the various components. A signal is conducted from the cell 23 by electrical leads 24 into a recorder 25, which is of the type which draws a graph showing the proportions of the various components in the eluent ilowing by line 22 into cell 23.

A portion of the helium in line 15 is suitably passed through line 26 controlled by valve 27 into cell 23 and flows outwardly therefrom by way of valve-controlled vents 28 along with the efuent gases from line 22.

. The assembly, including the column 20 and the thermal Gendujcfvity. @11.23. is suitably .housed in .a constant. temperature jacket 29 which maintains temperature at the desired constant level.

In practicing the present invention, a column having a height in -the range from about to about 30 feet and a diameter in the range from about 1A; to about 1/2 inch may be employed. A column which gives quite satisfac tory results is V4 inch in diameter and 2O feet long and may be packed suitably with 40 percent by Weight benzyl Cellosolve on Johns-Manville C-22 Firebrick having a mesh from about 40 to about 60 and which has been treatedj with a suitable acid` of a suitable strength. A temperature of about 86 F. may be used at a pressure of helium of about 5 pounds.

n' Although pressures of about 5 pounds may be suitable, pressures may range'from about l lto about 50 pounds per square inch gauge.

vThe presentV invention is particularly desirable and useful in that benzyl Cellosolvc as a chromatographic substrate gives an unexpected improvement in that the results are obtained'withou't delay, the column is operated at reasonable temperatures, which may be room temperature, 'and for mixtures such as water-acetone and C4 hydrocarbons substantially improved resolution s obtained over other substrates such as tricresyl phosphate, Octoil, -butyl Cellosolve, or phenyl Cellosolve. Octoil is di-2-ethyl-hexylsebacate.

ABesides resolving mixtures containing the compounds mentioned before, the present invention has been used successfully in resolving a mixture of 1,3-butadiene, lbutene,trans-butene-2, cis-butene-2, normal butane, and iso-butane. l

The present invention is quite useful in analyzing com plex gas mixtures, as has been indicated and shown, and may be used in control of vcommercial operations such as operations involving the extractive distillation of mixtures containing water, acetone and hydrocarbons, mix tures containing butylene and butadiene obtained from the dehydrogenation of butylene and in control of operations where butadiene Ais extracted with a solvent such as cuprous ammonium acetate.

The nature and objects of the present invention having been completely described and ilustrated, what we wish to claim as new and useful and secure by Letters Patent is:

1. A method for analyzing gaseous mixtures which comprises contacting a gaseous mixture in a stream of an inert gas with an elongated column of rebrick having a mesh size in the range from about to about 60l at ten'lperatures in the range from about 60l to ,about 120 F. and for a time within the range from about 5 to about 90 minutes, said iirebrick being employed with benzyl Cellosolve as a substrate, whereby said mixture is separated into its components.

2. A method for analyzing gaseous mixtures which comprises contacting a gaseous mixture in a stream of helium with an elongated column of rebrick having a mesh size in the range from about 40 to about 60 at ternperatures in the range from about to about 120 F. and for a time within the range from about 5 to about minutes, said lirebrick containing 40% by weight of benzyl Cellosolve as a substrate, whereby said mixture is separated into its components.

3. A method for analyzing gaseous mixtures which comprises contacting a gaseous mixture in a stream of an inert gaswith an elongated column of a support having a mesh size in the range from about 40 to about 60 at temperatures in the range from about 60 to about F. and for a time within the range from about 5 to about 90 minutes, said support being employed with benzyl Cellosolve as a substrate, whereby said mixture is separated into its components.

4. A method in accordance with claim 3 in which the gaseous mixture contains a hydrocarbon.

5. A method in accordance with claim 3 in which the gaseous mixture contains hydrogen sulfide.

. 6. A method in accordance with claim 3 in which the gaseous mixture contains sulfur dioxide.

7. A method` in accordance with claim 3 in which thev gaseous mixture contains an oxygenated compound.

8. A method in accordance with claim 3 in which the gaseous mixture contains air. v

9. A method for analyzing gaseous mixtures which comprises contacting a gaseous mixture in a stream of an inert gas with an elongated column of diatomaceous earthl i References Cited in the tile of this patent Vapour Phase Chromatography by D. H. Desty, Academic Press Inc., Publishers, New York, N. Y., 1956, pages 98 to 105. l 

1. A METHOD FOR ANALYZING GASEOUS MIXTURES WHICH COMPRISES CONTACTING A GASEOUS MIXTURE IN A STREAM OF AN INTER GAS WITH AN ELONGATED COLUMN OF FIREBRICK HAVING A MESH SIZE IN THE RANGE FROM ABOUT 40 TO ABOUT 60 AT TEMPERATURES IN THE RANGE FROM 60* TO ABOUT 120*F. AND FOR A TIME WITHIN THE RANGE FROM ABOUT 5 TO 